diff --git a/target/sparc/cpu.h b/target/sparc/cpu.h
index dda811503b..462bcb6c0e 100644
--- a/target/sparc/cpu.h
+++ b/target/sparc/cpu.h
@@ -574,7 +574,7 @@ struct SPARCCPUClass {
 
     DeviceRealize parent_realize;
     ResettablePhases parent_phases;
-    sparc_def_t *cpu_def;
+    const sparc_def_t *cpu_def;
 };
 
 #ifndef CONFIG_USER_ONLY